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<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      const info = {
        // css: {
        //   "border-color": {
        //     bgcolor: "red",
        //   },
        // },
        // say() {
        //   console.log("hello");
        // },
      };
      // ?.[]
      console.log(info.css?.["border-color"].bgcolor);
      // ?.()
      console.log(info.say?.());
    </script>
  </body>
</html>
